Creating solar-enriched fuelsAustralian research organisation CSIRO, in collaboration with industry partner Solar Systems, has demonstrated a process for integrating solar thermal energy and methane gas.
A range of solar-enriched fuels and synthesis gas - carbon monoxide (CO) and hydrogen (H2) - are produced.
These can be used as power generation fuel gas, as metallurgical reducing gas or as chemical feed stock - methanol production for example A demonstration facility, designed to process 44kW thermal of natural gas, is being operated by CSIRO. It includes all steps in the process with key aspects of the chemistry, reactor design and power generation potential confirmed.
This technology produces a gas with up to 40% of its energy value as embodied solar energy. If implemented by industry, the technology has the potential to reduce greenhouse emissions significantly.
The centrepiece of the facility is a twin-axis tracking paraboloidal solar thermal concentrating dish, which was designed and constructed by Solar Systems. The dish has been modified for optimum solar thermal performance.
This required increasing the control of the tracking mechanisms as well as modifying support and gas delivery arms to hold the heavier methane-reforming reactor.
It also involved ensuring the safe operation of the dish in higher winds than previously experienced.
Before starting the project, CSIRO had already proved the performance of a small reactor for reforming methane gas with the addition of steam in the laboratory. The operation was scaled up to enable it to match the solar delivery from the dish and the flow-rates of the fuel gas and water, in order to deliver a quality syngas. The team also developed the two main chemical processes involved at laboratory scale and then incorporated them into the full-scale facility.
The main chemical processes are:
- reforming of methane-containing gases, using concentrated solar energy to generate a mixture of CO and H2; and
- the option for further conversion of this gas to H2 and CO2 followed by recovery of CO2 in a concentrated form, as required for any subsequent CO2 disposal or utilisation scheme.